1. Field of the Invention
The present invention relates generally to a scanning window, and more particularly to an assembly structure for a glass disposing on the top of an image scanning device. A sheet is put on the glass and scanned by a carriage module. The image scanning device could be a flatbed scanner or a sheet-fed scanner. The structure is used to support the glass so that it can be fixed in the housing of the image scanning device.
2. Description of the Prior Art
An image scanning device of prior art includes a housing, a glass, and a carriage module. Since the glass is disposed in the housing and adjacent to the top thereof, an appropriate support is required for the positioning of the glass. A carriage module is disposed in the housing and capable of reciprocating motion to acquire images of a sheet to be scanned and perform image processing operations.
As FIG. 1 shows, the image scanning device has a plurality of mounting bases 12 (only one mounting base is shown in the figure) at the bottom of the housing 10 with a support 14 inserted in the mounting base 12. A glass 18 is positioned between the lower surface of the top surface 102 of the housing 10 and the top surface 16 of the support 14. Since the distance between the mounting base 12 and the top surface of the housing 10 is lengthy, the structural strength of the upper housing of the housing 10 is relatively weak. Moreover, when the housing 10 is molded, the cooling water for cooling down the mold tends to be constrained and consequently longer cooling cycles are required to avoid deformation.
Though screw nuts (not shown in the figure) can be embedded in the mounting base 12 for fixing the support 14 to the mounting base 12, extra costs are required for parts and thermal operations to embed the nuts in the mounting base 12.
In addition to the mounting base 12, the carriage module (not shown in the figure) in reciprocating motion is disposed at the bottom of the housing 10. With this structure, the housing 10 must have relatively greater length and width to prevent collision of the mounting base 12 and the carriage module in motion.
FIG. 2 shows another supporting device with a plurality of supports 20 (only one is shown in the figure) screwed beneath the top surface 102 of the housing 10. A height difference exists between one end of the support 20 and the top surface 102, and the glass 18 is positioned by embedding each side thereof in the gap formed due to the height difference.
However, since a support 20 is screwed to the top surface 102, the strength of the top surface 102 may be affected by screwing the support 20 and, in turn, the support 20 may not be well fixed in the position and the capability thereof to support the glass 18 is affected. Moreover, since the support 20 is screwed to the side of the top surface 102, the top surface 102 and the entire housing 10 must have the greater length and width to provide more space for screwing the support 20.